/*
 * Copyright 2011 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package org.protobee.util;

import java.util.Iterator;
import java.util.NoSuchElementException;

// modified by making public
public class CombinedIterator<E> implements Iterator<E> {

  private final Iterator<E> i1;
  private final Iterator<E> i2;
  private Iterator<E> currentIterator;

  public CombinedIterator(Iterator<E> i1, Iterator<E> i2) {
    if (i1 == null) {
      throw new NullPointerException("i1");
    }
    if (i2 == null) {
      throw new NullPointerException("i2");
    }
    this.i1 = i1;
    this.i2 = i2;
    currentIterator = i1;
  }

  public boolean hasNext() {
    boolean hasNext = currentIterator.hasNext();
    if (hasNext) {
      return true;
    }

    if (currentIterator == i1) {
      currentIterator = i2;
      return hasNext();
    } else {
      return false;
    }
  }

  public E next() {
    try {
      E e = currentIterator.next();
      return e;
    } catch (NoSuchElementException e) {
      if (currentIterator == i1) {
        currentIterator = i2;
        return next();
      } else {
        throw e;
      }
    }
  }

  public void remove() {
    currentIterator.remove();
  }
}
